Heat treating furnace



Nov. 21, 1961 w. E. HlNZ HEAT TREATING FURNACE 3 Sheets-Sheet 1 Filed Nov. 1958 hqlll' INVENTOR.

WA TER E H l N Z A T TO NEYS Nov. 21, 1961 w. E. HINZ HEAT TREATING FURNACE 3 Sheets-Sheet 2 Filed NOV. 28, 1958 FIG- 2- INVENTOR.

WA TER E-H|N Mi ATTOR N YS Nov. 21, 1961 w. E. HINZ HEAT TREATING FURNACE 3 Sheets-Sheet 3 Filed NOV. 28, 1958 R. E m

WALTER E- HINZ ATTORN Y S Unite The present invention relates in particular toheat treating equipment for the hardening, drawing, annealing, etc., of metal parts. A unitary heat treating furnace of great compactness and little cost is provided to supplant existing complex types of heat treating apparatus, in which the parts to be treated are conveyed on endless chain-type belts of great length, occupying great floor space, needless to say. However, as will appear as the description proceed-s, the principles of the invention are adaptable to other sorts of material handling and treatment equipment, in which similar advantages of compactness in regard to necessary fioo-r space, greatly decreased cost of production, increased ease of supervision and maintenance, and the like, may be obtained under the principles of the invention.

It is an object of the invention to provide a unitary heat treating or related equipment of this type, in which parts to be treated are conveyed rotatively on a series of vertically spaced tiers or rotating trays, each subdivided by partition structure into a plurality of circumferentially spaced compartments. Provision is made for sequentially discharging gravitationally the contents of one tray cornpartment into compartments of a tray or trays therebeneath as the rotation of the tiers progresses.

Thus, as the chamber in which the tiers of trays are rotatably mounted is heated, the parts undergoing treatment are progressively elevated in temperature and are subjected to the desired treating tempenature, depending upon the type of treatment performed, for a desired period of time, depending upon the number of tray tiers, the number of subdivisional compartments thereof and the speed of rotation of the tray structure.

Another object is to provide equipment of the sort described, in which each tray compartment has a bottom plate pivotally mounted along one edge of the compartment, being preferably perforated and foraminated for improved heat distribution, these tray bottoms being automatically controlled to drop away at a predetermined point in the rotation of their respective trays and thereby discharge the contents of the compartment in question to a tray compartment of a tier rotating therebeneath.

Yet another object is to provide equipment as described, in which the automatic dropping of the tray compartment bottom is under the control, in the case of each tier, of a cam rail upon which a follower rod carried by the compartment bottom rides in the rotation of its tray. The cam rail is preferably an annular one secured to the wall of the chamber in which the tiers are mounted, and is interrupted for an interval of its periphery, in which zone or sector of the rotation of the follower drops downwardly to cause the compartment bottom to discharge the compartment contents.

In further accordance with the invention, following a traverse of the discharge zone or sector, the follower re-engages an inclined cam portion of the rail and is elevated back to normal horizontal position.

'In accordance with a still further object, the zones or sectors of interruption of the respective cam rails for the several vertically spaced tray tiers are spaced circumferentially about the axis of their rotation, so that following discharge of objects from one tray compartment into that of the next lower tier, the objects will be rotatably transported in the compartment of that tray somewhat less than 360 before being in turn discharged to the next lowermost tier.

In general, it is an object to provide a heat treating dtates Patent ice or like apparatus of the sort referred to above which is FIG. 2 is a view in horizontal section along line 22 of- FIG. 1;

FIG. 3 is a view in vertical section along line 3-3 or FIG. 2, certain operating components of the equipment being more or less schematically shown; and I FIG. 4 is a fragmentary view in enlarged scale and vertical section along line 4-4 of "FIG. 2, showing a detail of the pivoting or hinging means for a tray compantment bottom plate.

As is well known in the heat treating art, the endless chain or belt conveyor type of equipment commonly employed in transporting parts to be drawn, annealed, etc., through the heating oven or chamber is inherently extremely space consuming. The apparatus or furnace of the invention, generally designated by the reference numeral 10, is, on the contrary, so decidedly compact that a conservation in needed floor space of as much as 400%, compared with the currently employed conveyor type, is possible in a typical installation of the improvement to handle a comparable output.

The furnace it) generally comprises an external housing or hollow body 11 of desired size and outline to accommodate the internal provisions to be described. The housing 11 may be constituted of an upright external sheet metal shell 12, an inner similar and smaller shell 13, spaced therefrom and of lesser height, the shells 12, 13 being closed by sealed top plates 14, 15, respectively, with a tubular loading chute '16 of adequate size communicating with the interior of housing 11 through the top plates l4, 15.

The interior of the housing 11 is subdivided, as by partition structure including a vertical wall 17 and a horizontal base member 18, into a heating chamber 20*, proper, separated from an upright return duct 21 by the upright partition member 17, and a fan housing space 22 separated from chamber 20 by the base'member 18; and a further upright Wall or partition member 23 separates the housing 22 from arecess 24 of the furnace in which various operating components are suitably mounted.

These components include an electric drive motor 25 of suitable rating, preferably equipped with an appropriate variable speed output device 26 operating on an upright axis; and a fan motor 28 by which a fan or blower 2 9 in the housing space 22 is driven is also disposed in recess 24. A suitable heating unit 30 is disposed at the bottom of return duct 21 to heat and reheat the circulating air.

The partition and base members 17, 18 are preferably fabricated in a manner similar to the construction of the main housing or body 11, and the spaces between the sheet metal shells thereof are filled with suitable insulating material 32, the same being true of the partition or wall member 23. Structural details of this sort constitute no part of the invention, and are susceptible of considerable modification, as called for by the requirements of the particular installation.

Similarly, the nature and particular arrangement of the components 25, 28, 29 and 30 is not the subject matter of the invention, hence they have been shown only sche-' matically.

As illustrated in FIG. 3, the horizontal base member 18 will be provided with a suitable hot air circulating passage 34 from the chamber 20 to the fan housing space 22; and the top of partition member 17 terminates short of the top of housing 11, so that a continuous path of circulation of air heated by the unit is defined, as indicated by arrow in FIG. 3, i.e., from the chamber 20 through duct 21, heat unit 30, fan 29 and passage 34 back to the chamber 20.

A tiered tray unit in accordance with the invention is generally designated 35 and is mounted for rotation within the chamber 20 on a vertical shaft 36 journalled at its top and bottom in the top of the housing 11 and the horizontal base member 18 of the latter. This shaft may be made of like aligned sections 37 drivingly con nected by toothed connections, which will permit thermal expansion under elevated heat treating temperatures. The shaft has secured thereon, for rotation therewith, a plurality of vertically spaced tray tiers, shown as four in the illustrated embodiment, each of identical construction. It is therefore evident that, depending upon the desired capacity of the furnace, any desired number of similar tray units may be employed.

Each of the tray tier units 35 comprises a tubular spacer or hub 38 (of a desired axial length, depending upon the number of tiers to be employed) sleeved on, and drivingly secured in an appropriate way to, the shaft 36 for rotation with the latter. The hub 38 supports from beneath a central spider or hub member 39 of a circular horizontal tray, generally designated 40. This driving connection may be effected by drivingly connecting the hub 38 to the member 39, or by a direct driving connection of the latter to shaft 36.

The top portion of the tray 40 includes an annular upright confining rim or wall 41 of circular shape, which rotates in inwardly spaced relation to the wall of the chamber 20, and it will be understood that this wall may be made generally concentric with the tray or tier unit 36 by appropriately shaping the upright partition member 17 and a coacting wall portion of the housing 11.

The hub member 39 is formed to provide an annular upright inner tray wall 42 outwardly coaxial with its axis, and the annular space between outer upright tray wall 41 and this inner wall 42 is subdivided by radial upright dividers or partitions 43 into a plurality of equal sized, sector shaped compartments 44; it is evident that thetray structure as thus constituted may be very inexpensively produced as a single casting, although a built-up construction is also contemplated.

Each of the several tray compartments 44 is individually bottomed by a pivoted wing plate 45, preferably of a foraminated, perforated or screen-like character in the interest of both improved air circulation and lightness in weight, as well as enabling it to be readily kept clean.

As best shown in FIG. 4, the compartment partitions are preferably formed in a downwardly opening recessed vertical cross section of inverted-V outline to accommodate and shield from above an elongated radial hinge pin 47 for the bottom wing plate 45 of the compartment in question. The plate may be pivotally mounted on the pin 47 in any suitable way, as by providing hub bosses 48 on a radial edge of the plate 45 to act as hinge collar elements. Hinge pins 47 extend through these bosses and are mounted at their opposite inner and outer ends in the hub 38 or inner arcuate tray wall 42 and in the outer tray wall 41. It is evident that other types of simple plate hinging means may be employed.

The shape and area of bottom plates correspond approximately to the respective tray compartments 44, the free radial edge 49 of the plate slightly underlapping the adjacent partition if desired; and adjacent and along this radial edge each plate has a cam follower rod 50 secured thereon, as by welding, to its lower side.

The outer ends of the hinge pins 47 and the outer ends of follower rods 50 extend outwardly of the tray 40,

4 where they ride on an arcuate cam rod 52 mounted fixedly by a plurality of brackets 53. As appears H1 FIGS. 1 and 3, each cam rod is of generally circular outline, disposed in the main in a horizontal plane and the several rods are vertically spaced in accordance with the spacing of the respective tiers 40.

Each cam rod 52 has a drop off end 54 in a horizontal plane and, spaced somewhat therefrom in the circumferential sense, an upwardly inclined restoring cam portion 55. The spaces between the respective cam drop off ends 54 and restoring portions 55 of the respective cam rods or tracks 52 are staggered progressively about the circumference of the chamber 20, so in any given rotative cycle the respective vertically spaced trays dis= charge at different angularly spaced points, insuring that discharge from one tray compartment 44 will be made to an empty compartment therebeneath, the charge being thereupon transported rotatively through somewhat less than 360 until it, in turn, is dropped onto a lower tray.

In operation, with the objects to be heat treated charged into the furnace 10 through the upper charge chute 16, they are transported by the uppermost tray unit 35, the respective hinge rods 47 and cam follower rods 59 riding the respective cam rods 52 and sustaining associated compartment bottom plate 45 horizontally. Upon arrival at the drop off end 54 of the last named rods, the bottom plate dumps its content to a tray compartment therebeneath; and as the travel of the tray unit proceeds, the follower rod strikes and rides up the restoring cam portion of its cam rod. This operation takes place successively at all tiers, until the bottommost tier discharges onto an inclined discharge chute 57 and, in turn, into a tote box 58 or other suitable receptacle As illustrated in FIG. 3, the drive of the segmented shaft 36 may be through the agency of a suitable chain and sprocket connection 59 to the lower end of the shaft. Other provisions in regard to heating and circulartion of heating medium are conventional and form no part of the present invention. As to operating compon ents of the latter, they are shown only schematically. with no attempt to reproduce actual industrial structure which may incorporate the principle of the invention.

What I claim as my invention is:

1. Heat treating equipment comprising a chamber hav ing means for the continuous recirculatory flow of heating medium therethrough, a tray mounted to rotate about a vertical axis in said chamber, said tray having radial partition means subdividing the same into a plurality of material-receiving compartments, bottom members for said compartments pivotally mounted on said tray for movement relative thereto to uncover at least a portion of the bottom area of the respective compartments in the rotation of the tray and thereby downwardly discharge the content thereof, said partition means comprising radial members of downwardly opening recessed cross section on the tray and said bottom members having generally radial edges provided with hinge elements by which they are hinged on said tray substantially along and beneath said radial partition members, thereby being shielded by said radial members from above means sustaining said bottom members of said tray in compartment-bottoming position during a portion only of the rotation of the tray, and means to rotate said tray.

2. Heat treating equipment comprising a chamber having means for the continuous recirculatory flow of heating medium therethrough, a tray mounted to rotate about a vertical axis in said chamber, said structure comprising a tray having radial partition means subdividing the same into a plurality of material-receiving compartments, bottom members mounted on said tray for movement relative thereto to uncover at least a portion of the bottom area of the compartments thereof in the rotation of the tray and thereby downwardly discharge the content thereof, said partition means comprising radial members of downwardly opening recessed cross section on the radial members from above means sustaining said bottom members in compartment-bottoming position during a portion only of the rotation of the tray, comprising a spaced cam track generally concentric of the axis of the tray and adjacent the outer peripheral travel of the latter which is engageable by a free edge portion of the bottom members in the rotation of the respective trays, and means to rotate said tray structure.

3. Heat treating equipment comprising a chamber of substantial vertical, as compared to horizontal, dimension having means for the continuous recirculatory fiow of heating medium therethrough, a tiered tray structure means mounting said tray structure to rotate about a vertical axis in said chamber, said structure comprising a pluraliy of similar horizontal trays in coaxial, vertically spaced relation, said mounting means comprising an upright shaft including a plurality of axially aligned shaft sections interlocked for rotation as a unit, and hub members on the respective trays encircling said shaft, each tray having radial partition means subdividing the same into a plurality of material-receiving compartments, bottom members for said trays mounted thereon for movement relative thereto to uncover at least a portion of the bottom area of the compartments thereof in the rotation of the tray structure and thereby downwardly discharge the content thereof, said partition means of each tray comprising radial members of downwardly opening 6 recessed cross section thereon and said bottom members having generally radial edges provided with hinge elements by which they are hinged on said respective trays substantially along and beneath said radial partition members, thereby being shielded by said radial members from above, and means sustaining said bottom members 1 of said respective trays in compartment-bottoming position during a portion only of the rotation of the tray thereof, comprising vertically spaced cam tracks mounted generally concentric of the axis of thetray structure and adjacent and around the Wall of said chamber, said bottom members each having an element extending along a radial free edge portion of the respective bottom members and slidably engaging a cam track in the rotation of the respective trays, and means to rotate said tray structure, said sustaining cam tracks releasing the bottomrnembers of the respective trays at different, angularly spaced further portions of their respective paths of rotation to downwardly discharge the compartment content.

References Cited in the file of this patent UNITED STATES PATENTS 1,515,103 Gage Nov. 11, 1924 1,529,808 Pike et al. Mar. 17, 1925 1,769,491 Crossman July 1, 1930 1,961,143 Gehnrich June 5, 1934 2,483,592 Nichols et al. Oct. 4, 1949 FOREIGN PATENTS 448,575 Germany Aug. 22 

